JP3323759B2 - Pulse width modulation converter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse width modulation converter having an AC reactor on the input side, and more particularly, to a power supply having less distortion even if a power supply voltage or a main circuit of the pulse width modulation converter has waveform distortion. The present invention relates to a pulse width modulation converter device capable of flowing a current.

[0002]

2. Description of the Related Art In recent years, there has been a problem that a harmonic current of a power electronic device causes an obstacle to a power system.
For this reason, recently, guidelines for power supply current harmonic regulation have been set, and in power electronics devices, suppression of power supply harmonics has become an essential requirement.

Therefore, for example, Japanese Patent Application Laid-Open No. Sho 59-194697
This publication discloses a voltage-type PWM (pulse width modulation) converter in which the power supply current is sinusoidal by feedback control of the power supply current corresponding to the commercial power supply frequency.

In this converter, a power supply current amplitude command is output so that the DC voltage between the smoothing capacitors coincides with the command value. Under this amplitude command, a sinusoidal power supply current synchronized with the power supply voltage is output. By outputting a converter voltage command so that the actual power supply current follows the command, the power supply current is made to have a sine wave shape.

[0005]

In the above prior art, no consideration is given to suppression of higher-order harmonics, and there is a problem in that a sufficient power supply current is converted into a sine wave. That is, the above-described conventional technology forms a feedback control system for the power supply frequency, and its response is set to about 1000 rad / s (corresponding to a response time constant of 1 ms).
The control response is insufficient for the 7th harmonic current component,
It is difficult to suppress these harmonic current components.

For this reason, if harmonic currents centering on the fifth and seventh orders flow due to the distortion of the power supply voltage or the output voltage of the PWM converter, etc., the power supply current of the harmonics cannot be suppressed only by the current control system of the fundamental wave. .

Therefore, in the prior art, an AC reactor (hereinafter, referred to as ACL) is provided on the power supply side to thereby make the current a sine wave. However, in the case of a PWM converter having such an ACL, the power supply voltage is reduced. And the harmonic voltage distortion amount ΔVn and the harmonic current component ΔIn in the PWM converter.
Can be expressed by the following equation (1).

[0008] ΔIn (%) ｎΔVn (%) · 100 / [(% X of ACL) · n] (1) where, ΔIn (%): nth order of power supply current (AC reactor current) harmonic content (%) ΔVn (%): n -order harmonic content of the power supply voltage or PWM converter output voltage (%) n:% orders ACL harmonics X: in passing the rated supply current The ratio of the voltage drop due to the ACL to the power supply voltage (%) Equation (1) indicates that the magnitude of the harmonic component of the power supply current is proportional to the magnitude of the harmonic voltage component included in the power supply voltage or the PWM converter. Is inversely proportional to the inductance of

For example, assuming that the harmonic content when n = 5 is 2%, that is, ΔV5 = 2%, the harmonic regulation guideline value for a consumer who receives power at high voltage is ΔI5 =
Since it is 4%, an ACL having an inductance of 10% X or more is required to suppress the value to this value or less.
Considering the influence of the distortion of the power supply voltage and the PWM converter voltage, a larger ACL, for example, 15 to 20% X ACL is used.
Is used.

That is, in the prior art, unless an ACL having a large inductance is used, the distortion of the power supply current due to the distortion of the power supply voltage or the PWM converter voltage can hardly be suppressed. As a result, the harmonic regulation is satisfied. Required an ACL with a large inductance.

As a result, in the prior art, the volume is large,
A, heavy and expensive, with large inductance
There is a problem that a CL is required, which results in an expensive device.

An object of the present invention is to reduce the harmonic component of the power supply current (ACL current) without increasing the inductance of the ACL even if the power supply voltage or the voltage of the PWM converter is distorted. An object of the present invention is to provide a low-cost PWM converter device.

Another object of the present invention is to provide a PWM converter device in which the order of harmonic current to be suppressed can be arbitrarily selected and set.

[0014]

An object of the present invention is to generate a power supply voltage and a compensation voltage necessary for canceling a harmonic voltage component by a PWM converter, superimpose the compensation voltage on the AC side voltage of the converter, and obtain an equation (1). Harmonic content ΔVn (%) explained in
Is equivalently approached to zero.

Since a difference voltage between the power supply voltage and the converter AC side voltage is applied to the ACL (AC reactor), a harmonic voltage equivalent to the power supply voltage and the output voltage of the PWM converter is superimposed on the AC side voltage of the converter. As a result, the harmonic current flowing through the ACL can be reduced.

For this reason, the harmonic current component flowing through the ACL is converted from a fixed coordinate axis (uvw axis) to a rotating coordinate axis (dq axis) and detected as a DC amount. The final converter voltage command is calculated by calculating the compensation voltage of the second harmonic current, converting the compensation voltage into an AC amount, and adding it to the output of the current control system of the fundamental wave.

Thus, the voltage on the AC side of the converter can be compensated so that each harmonic current is almost eliminated, and the harmonic current can be greatly reduced. That is, since a voltage substantially equal to the power supply voltage and the harmonic voltage included in the PWM converter is superimposed on the AC side voltage of the converter, ΔVn (%) shown in Expression (1) becomes equivalently close to zero, The power supply harmonic current also becomes substantially zero. As a result, the harmonic current component due to the harmonic components of the power supply voltage and the output voltage of the PWM converter can be suppressed without increasing the inductance value of the ACL.

By the way, the harmonic voltage component included in the power supply voltage and the output of the PWM converter is generally 5
Next is the 7th order. However, for example, from the 7th order component, 11
In the case of a power supply having a large next component, it is better to compensate for the fifth and eleventh orders. Therefore, the other object is achieved in that the order of the harmonic current to be compensated can be arbitrarily selected and set by manual operation according to the state of the power supply in which the PWM converter device is installed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a PWM converter according to the present invention will be described based on the illustrated embodiment. FIG. 1 shows an embodiment of the present invention, in which 1 is an AC power supply, 2 is an ACL (AC reactor), and 3 is a PWM.
The converter main circuit, 4 is a smoothing capacitor, and 5 is a load.

The PWM converter main circuit 3 includes an ACL 2
, And three-phase AC power of R, S, and T is supplied from the AC power supply 1, and this AC power is converted into DC power of a predetermined voltage Vdc by the PWM converter main circuit 3,
After being smoothed by the smoothing capacitor 4, it is supplied to the load 5.

Further, the PWM converter main circuit 3 includes:
The configuration is such that the inverse conversion operation control can be performed as necessary, and it is possible to cope with the power regeneration operation.

The load 5 is, for example, a main circuit of an inverter for driving an induction motor, and is supplied with DC power of a voltage Vdc.
This is converted into three-phase AC power having a predetermined variable voltage and variable frequency, and an induction motor (not shown) is driven at a variable speed.

Next, reference numeral 6 denotes a DC voltage detector, 7 denotes a DC voltage controller, and the DC voltage detector 6 detects a DC voltage Vdc appearing at both ends of the smoothing capacitor 4, and detects the DC voltage Vdc. The DC voltage controller 7 compares the output Vdc of the DC voltage detector 6 with the DC voltage command Vdc ^*, and generates an effective power component current command Iq ^* as a difference between them. .

Reference numeral 8 denotes an AC voltage detector, 9 denotes a power supply voltage phase calculator, and the AC voltage detector 8 functions to insulate and detect the voltage Vr of the AC power supply 1.
From the voltage Vr detected by the voltage detector 8, it functions to detect the power supply voltage phase θr of the R phase among the three-phase AC voltages.

Reference numeral 10 denotes a current detector (CT), 11 denotes a fundamental wave current control unit, which detects the current detector 10 and the AC side current of the PWM converter main circuit 3 serving as a power supply current, that is, the currents iu and iw of the ACL 2. The fundamental current control unit 1
1 is an effective power component current command Iq ^* and a power supply voltage phase θr,
In addition, the currents iu and iw of the ACL 2 are input, and these function to output converter AC side voltage commands Vux, Vwx and Vvx.

Next, the details of the fundamental wave current controller 11 will be described with reference to the block diagram of FIG. First, UVW / dq
The conversion processing unit 12 sets θd = θr−π / 2 and
(2) is calculated, and the actual reactive power component current Id is calculated.
Then, the effective power component current Iq is calculated.

Id = [(iu + 2iw) / √3] cosθd + iu · sinθd Iq = iu · cosθd − [(iu + 2iw) / √3] sinθd (2) Next, the non-interference current control processing unit 13 DC voltage controller 7
The effective power component current command value Iq ^*, which is the output of
And the reactive power component current Id becomes zero according to the reactive power component current command value Id ^* = 0, so that the command V of the rotation coordinate axis component of the basic converter AC side voltage vector is obtained.
Outputs qx and Vdx.

The dq / UVW conversion processing unit 14
Based on these commands Vqx and Vdx, calculation is performed by the following equation (3), and the converter AC-side voltage commands Vux, Vwx and Vvx, which are the basics of three-phase AC, are output.

Vux = Vdx · sinθd + Vqx · cosθd Vwx = (√3 / 2) (Vdx · cosθd−Vqx · sinθd) −Vux / 2 Vvx = − (Vux + Vwx) …………………………………… (3) Next, returning to FIG. 1, reference numeral 15 denotes a harmonic current compensating unit, a harmonic reference phase calculation processing unit 16, a harmonic current calculation processing unit 17, and a harmonic compensation voltage for each harmonic. A power supply voltage phase θr, a reactor current detection value iu,
iw is input and functions to output three-phase harmonic compensation voltage commands .DELTA.Vu, .DELTA.Vv, and .DELTA.Vw based on these, and are a main part of the present invention.

In the harmonic current compensator 15, first, in the harmonic reference phase calculator 16, the input power supply voltage phase θr is multiplied by n (n is the order of the harmonic), and the product n · Outputs θr. Next, each order harmonic current calculation processing unit 17 detects a harmonic current component of each order based on the product n · θr and the reactor current detection values iu and iw,
Corresponding to this, each order harmonic compensation voltage calculation processing unit 18
Thus, three-phase harmonic compensation voltage commands ΔVu, ΔVv, ΔVw are output.

Reference numeral 19 denotes a PWM signal generating unit, which is a converter AC side voltage command V output from the fundamental wave current control unit 11.
Based on signals Vux ^* , Vvx ^* , Vwx ^* obtained by adding three-phase harmonic compensation voltage commands ΔVu, ΔVv, ΔVw output from harmonic current compensator 15 to ux, Vvx, Vwx. Switching signal PWM for switching element control
It serves to generate a signal and supply it to the PWM converter main circuit 3.

Next, details of the harmonic current compensator 15 will be described with reference to FIG. First, the three-phase / two-phase converter 20
Then, the calculation according to the following equation (4) is executed, and the two-phase command iα,
Generate iβ.

Iα = iu iβ = (iu + 2 · iw) / √3 (3) Next, in the fifth-order dq converter 21a, the harmonic reference phase calculation is performed. A signal 5θr corresponding to n = 5 is input from the processing unit 16 as a reference phase signal, and a conversion from the fixed coordinate axis to a rotating coordinate axis corresponding to the fifth harmonic is performed by the following equation (5). , The fifth harmonic current Id5 for each phase,
Iq5, Igd5, and Igq5 are calculated.

Id5 = iα × cos (5 · θr) + iβ × sin (5 · θr) Iq5 = iα × [−sin (5 · θr)] + iβ × [cos (5 · θr)] Igd5 = iα × cos ( −5 · θr) + iβ × sin (−5 · θr) Igq5 = iα × [−sin (−5 · θr)] + iβ × [cos (−5 · θr)] (5) where Id5: 5 Reactive component current of positive phase at the fifth harmonic Iq5: Active component current of positive phase at the fifth harmonic Igd5: Reactive component current of negative phase at the fifth harmonic Igq5: Active component current of negative phase at the fifth harmonic Is output as a DC amount including a ripple current of the order of n ± 1. Therefore, each of the low-pass filters 22
The ripple currents are removed via a to 22d, and are output from each order harmonic current processing unit 17 as a signal of only the DC amount.

Next, in the 7th-order dq converter 21b, the operation of the equation (5) is performed in the same manner. This time, the harmonic reference phase operation processing unit 16 responds to n = 7 as a reference phase signal. The calculated signal 7θr is input, and the constant 5 in the equation (5) is calculated by replacing it with 7, thereby converting the fixed coordinate axis to the rotating coordinate axis corresponding to the seventh harmonic, and for each phase Calculate the seventh harmonic current Id7, Iq7, Igd7, Igq7,
Similarly, the ripple currents are removed via the low-pass filters 22e to 22h, respectively, and the signals are output from each order harmonic current processing unit 17 as signals of only the DC amount.

Next, each order harmonic compensation voltage calculation processing section 1
8, the gain processing units 23 a to 23
d, 23e to 23h, PI compensator (proportional-integral compensator) 2
4a to 24d and 24e to 24h are provided. First, for the fifth-order signal, the gain processing units 23a to 23d execute A
The amount of voltage drop of CL is calculated for each axis.
By performing PI compensation by 4a to 24d, the q-axis voltage compensation amount Vq5 in the positive phase at the fifth harmonic and the d-axis voltage compensation amount Vd5 in the positive phase at the fifth harmonic are q in the negative phase at the fifth harmonic. Axial voltage compensation amount Vgq5, and d-axis voltage compensation amount Vg of the fifth harmonic and the opposite phase
Output d5 respectively.

Next, for the seventh-order signal, the amount of voltage drop of the ACL is calculated for each axis by the gain processing units 23e to 23h, and then PI-compensated by the PI compensators 24e to 24h. The positive-order q-axis voltage compensation amount Vq7 at the seventh harmonic and the positive-phase d-axis voltage compensation amount Vd at the seventh harmonic
7, 7th-order harmonic and anti-phase q-axis voltage compensation amount Vgq7, and 7
A d-axis voltage compensation amount Vgd7 of the opposite harmonic and the opposite phase is output.

Here, the principle of calculating these compensation amounts will be described with reference to FIG. Considering that the n-th harmonic voltage of the voltage of the AC power supply 1 is ΔVrn and that a harmonic current ΔIun is generated by this, the AC current is calculated based on the harmonic current ΔIun.
The amount of voltage drop that appears in L2 is the converter AC side voltage ΔV
If given as un, then ΔVrn ≒ ΔVun, and theoretically the harmonic current ΔIun can be made zero.

At this time, as is clear from the voltage and current vector diagrams shown in the figure, the vector whose phase is advanced by 90 degrees from the current vector ΔIun becomes the voltage vector ΔVun. Therefore, the d-axis component of the current vector ΔIun is Idfn, the q-axis component is Iqfn, the d-axis component of the voltage vector ΔVun is Vdfn,
Assuming that the q-axis component is Vqfn, the relationship between these DC components is expressed by the following equation (6).

Vdfn = −Iqfn · n · ωL Vqfn = Idfn · n · ωL (6) where ω is the angular frequency of the power supply voltage, and L is the inductance value of the ACL. Therefore, the output of the low-pass filter 22a shown in FIG. 3 is obtained by the gain processing unit 23a with the positive-phase effective component current Idf5 when n = 5 in the equation (6).
Is the voltage drop amount Vqf5 of the ACL due to the positive-phase active component current Idf5, and the output of the low-pass filter 22b is the same positive-phase active component current Iqf5, and the gain processing unit 2
The output of 3b is the voltage drop amount Vdf5 of the ACL.

The same applies to the case of the opposite phase. In the equation (6), only ω becomes negative. Therefore, when the output of the low-pass filter 22c is n = 5 in the equation (6), The negative-phase reactive component current Igdf5 is applied to the gain processing unit 23c.
Is the voltage drop amount Vgdf5 of the ACL, and the output of the low-pass filter 22d is the active component current Igqf5
Thus, the output of the gain processing unit 23d becomes the voltage drop amount Vgqf5 of the ACL.

Accordingly, the harmonic voltage component corresponding to the harmonic current can be calculated from the above relationship, and PI
The outputs of the compensators 24a to 24d have the q-axis voltage compensation amount Vq5 of the positive phase at the fifth harmonic and the d-axis voltage compensation amount Vd5 of the positive phase at the fifth harmonic, respectively. q-axis voltage compensation amount Vgq
5, a d-axis voltage compensation amount Vgd5 of the negative order at the fifth harmonic is obtained. Similarly, the q-axis voltage compensation amount Vq7 of the positive phase at the seventh harmonic is output to the outputs of the PI compensators 24e to 24h, respectively. Then, the positive-order d-axis voltage compensation amount Vd7 at the seventh harmonic, the negative-phase q-axis voltage compensation amount Vgq7 at the fifth harmonic, and the negative-phase d-axis voltage compensation amount Vgd7 at the fifth harmonic are obtained. It is done.

Next, these voltage compensation amounts are converted from the rotating coordinate axis to the fixed coordinate axis by the inverse dq converters 25a and 25b. At this time, first, in the inverse dq converter 25a,
By inputting the signal 5θr corresponding to n = 5 from the harmonic reference phase calculation processing unit 16 and executing the calculation of the following equation (7), the harmonic compensation voltage of the DC amount can be changed to the AC amount Vα5, Vβ
5, and output as Vgα5 and Vgβ5.

Vα5 = Vd5 × cos (5 · θr) + Vq5 × [−sin (5 · θr)] Vβ5 = Vd5 × sin (5 · θr) + Vq5 × cos (5 · θr) Vgα5 = Vgd5 × cos (−5)・ Θr) + Vgq5 × [−sin (−5θr)] Vgβ5 = Vgd5 × sin (−5θr) + Vgq5 × cos (−5θr) (7) On the other hand, the same applies to the seventh order. , The reference phase of the inverse dq conversion in the inverse dq converter 25b is set to 7θr, and the constant of the above equation (7) is simply set to 7, whereby the inverse dq converter 2
From 5b, the harmonic compensation voltage of the DC amount is changed to the AC amount Vα7, Vβ
7, and output as Vgα7 and Vgβ7.

Next, these inverse dq converters 25a, 25b
As shown in the figure, the output of
The calculation based on the equation (8) is performed, and the fifth-order and seventh-order compensation voltages are added to obtain two-axis harmonic voltage compensation amounts ΔVα and ΔVβ.

ΔVα = Vα5 + Vgα5 + Vα7 + Vgα7 ΔVβ = Vβ5 + Vgβ5 + Vβ7 + Vgβ7 (8) And finally, a two-phase / three-phase converter 26 is used.
The following equation (9) is used to calculate the three-phase harmonic compensation voltage command ΔV from the two-axis harmonic voltage compensation amounts ΔVα and ΔVβ.
u, ΔVv, and ΔVw are obtained respectively.

ΔVu = ΔVβ ΔVv = − (√3 · ΔVα + ΔVβ) / 2 ΔVw = (√3 · ΔVα−ΔVβ) / 2 (9) Next, as a whole of this embodiment, The operation will be described. As described above, the PWM signal generator 19 includes the three-phase harmonics output from the harmonic current compensator 11 with the AC voltage commands Vux, Vvx, and Vwx of the converter output from the fundamental current controller 11. Wave compensation voltage commands ΔVu, ΔVv, Δ
The signals Vux ^* , Vvx ^* , Vwx ^* to which Vw is added are supplied. As a result, the PWM signal generator 19 outputs the main circuit based on the corrected signals Vux ^* , Vvx ^* , Vwx ^*. A switching signal PWM signal for switching element control is generated, and the PWM converter main circuit 3 is controlled.

At this time, the harmonic compensation voltage command Δ
As described above, Vu, ΔVv, and ΔVw are voltages substantially equivalent to the voltage of the AC power supply 1 and the harmonic voltage included in the PWM converter main circuit 3.
ΔVn (%) shown in equation (1) becomes equivalently close to zero, and the power supply harmonic current also becomes almost zero. As a result, ACL
The harmonic current component due to the harmonic components of the power supply voltage and the output voltage of the PWM converter can be sufficiently suppressed without increasing the inductance value of No. 2.

Therefore, according to this embodiment, even if the power supply voltage or the voltage of the PWM converter has distortion,
There is no need to increase the inductance of L2, and as a result, a compact, lightweight, low-cost PWM converter device can be obtained. Hereinafter, the reason will be described in more detail.

First, in the above embodiment, the order of the harmonic components to be suppressed is applied to the fifth and seventh orders. First, the reason will be described. Generally, the harmonic voltage component included in the commercial power supply is usually 5
The next and seventh orders are the main components. In addition, although the dead time is included in the control of the PWM converter, the output voltage distortion resulting therefrom becomes a fifth harmonic component. Therefore, in this embodiment, as described with reference to FIG. 3, compensation is performed for the fifth and seventh harmonic currents.

Next, if the power supply voltage or the output voltage of the PWM converter has distortion due to harmonics, as shown in the equation (1), the harmonic current corresponding to the power supply harmonic voltage of each order becomes A
It flows to CL2.

Although this reactor current includes a fundamental wave current, in this embodiment, as shown in FIG. 6, dq converters 21a and 21b are provided, and dq converters 21a and 21b are provided in the fifth and seventh power supply phases.
By performing the conversion and passing through the low-pass filters 22a to 22h, approximately the fifth and seventh harmonic current components can be detected by the DC amount.

In this embodiment, the gain processing units 23a to 23h apply ωL to the fifth and seventh harmonic currents.
To calculate the amount of voltage drop of the ACL,
a to 24h, the compensation voltage is output, so that the power supply voltage or PW
Feedback control is performed so as to cancel the voltages corresponding to the fifth and seventh harmonic voltages included in the M converter.

As a result, from the reactor current, the fifth-order, seventh
The next harmonic current component is almost eliminated, and the dq converter 2
The average value of the outputs 1a to 21h becomes a steady state when the output is zero, and all the outputs of the gain processing units 23a to 23h can be made zero. In this case, the compensation voltage is held at the output of the integrator in each of the PI compensators 24a to 24h.

Next, FIG. 5 shows the embodiment of FIG.
This is an example of an operation waveform obtained by simulation. In this example, an AC power supply in which a fifth harmonic of 10% and a seventh harmonic of 7% are added to a sine wave AC is used, and an AC reactor of 15% X
This is a waveform when a simulation is performed under the conditions of (1) and (2).

In FIG. 5, Vr is a power supply voltage waveform and Δr
Vr is a harmonic voltage waveform obtained by adding the 5th harmonic of 10% and the 7th harmonic of 7%. Therefore, the power supply voltage waveform Vr is
The waveform has a waveform obtained by adding the fifth harmonic of 10% and the seventh harmonic of 7% to the alternating current of the sine wave.

In FIG. 5, first, the upper diagram (a) shows the waveform in the prior art, in which the harmonic current compensator 15 in the embodiment of the present invention is not provided. Therefore, the compensation voltage ΔVu is At zero, the power supply current iu therefore remains largely distorted.

On the other hand, FIG. 5B in the lower part of FIG. 5 shows the case of the above-described embodiment of the present invention, in which the harmonic current compensator 15 is added and the harmonic current compensation is performed. Accordingly, the harmonics of the reactor currents iu and iw become substantially zero in a steady state, and the average value of the outputs of the dq converters 21a and 21b in FIG. 3 becomes zero.

However, the compensation voltage is held by the operation of the PI compensators 24a to 24 so that the harmonic current becomes zero. As a result, the compensation voltage ΔVu becomes higher as shown in FIG. The voltage command becomes almost the same as the wave voltage ΔVr,
This voltage is superimposed on the converter AC side voltage. As a result, a harmonic current flows with a difference voltage between the harmonic voltage ΔVr and the compensation voltage ΔVu, and the harmonic current becomes almost zero.

Therefore, according to the above embodiment, the AC side voltage of the PWM converter main circuit 3 can be output so as to cancel out the harmonic voltage components included in the power supply voltage and the PWM converter output voltage. Even when the voltage distortion is large, the effect that the harmonics of the power supply current can be greatly reduced is obtained. As a result, even if the inductance of the AC reactor is reduced, there is no possibility that the harmonic components of the power supply current increase. Therefore, there is an effect that the AC reactor can be reduced in size, weight, and price, and the PWM converter device can be reduced in size, weight, and price.

In the above description, it has been described that the entire control operation is performed by a hardware configuration. However, in actuality, a software configuration by a computer program may be used. FIG. 8 is a flowchart showing the process in this case.

The above is the description of the first embodiment of the present invention. Next, another embodiment of the present invention will be described. First, FIG. 6 shows a harmonic current compensator 11 according to the second embodiment of the present invention, and the overall configuration is the same as that of the embodiment shown in FIG. The difference of the harmonic current compensator 11 shown in FIG. 6 from the embodiment shown in FIG. 3 is that the low-pass filters 22a to 22a are omitted.

As shown in FIG. 6, even if the low-pass filters 22a to 22a are omitted, since an integrator exists in the PI compensation 24a to 24, a considerable filter function can be obtained by the function of the integrator. As a result, according to the embodiment of FIG. 6, substantially the same operation as that of the embodiment of FIG. 3 can be obtained, and the configuration is simplified.

In the embodiment shown in FIGS. 3 and 6,
Although the PI compensators 24a to 24c are used, an integral compensator may be used instead. In this case, substantially the same effects as those of the embodiments of FIGS. 3 and 6 can be obtained.

Next, FIG. 7 shows a third embodiment of the present invention, which differs from the embodiment of FIG.
The point is that a setting device 27 is provided. This compensation order n setting device 2
Reference numeral 7 is configured so that the order n of the harmonic used in the processing by the harmonic reference phase calculation processing unit 16 can be arbitrarily selected and set by manually operating the same.

As a result, for example, 11
In the case of a power supply having a higher order harmonic, the compensation order n setting device 27 is manually operated to select and set the fifth and eleventh harmonics. The product n · θr, which is the output of the phase calculation processing unit 16, is
5θr and 11θr are obtained, and the operation necessary for compensating the fifth and eleventh harmonics can be obtained.

Therefore, the control processing according to the third embodiment is shown in a flowchart in FIG. According to the embodiment of FIG. 7, harmonics of any order can be reduced as necessary, and as a result, optimum harmonics reduction is always achieved regardless of the state of the AC power supply to be applied. It has the effect of being obtained.

[0068]

According to the present invention, the PWM is controlled so as to cancel the power supply voltage and the harmonic voltage component contained in the PWM converter.
Since the AC side voltage of the M converter can be controlled, the harmonic component of the power supply current can be reduced even when the voltage distortion is large,
As a result, even if the inductance of the AC reactor is reduced, the magnitude of the harmonic current component can be suppressed to the harmonic power supply current regulation value or less, and the PWM converter can be reduced in size, weight, and price. is there.

Furthermore, since the order of the harmonic to be compensated can be easily selected and set by manual operation, the harmonic of an arbitrary order can be reduced, and the harmonics can be reduced regardless of the state of the power supply. There is an effect that optimal harmonic reduction can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a pulse width modulation converter device according to the present invention.

FIG. 2 is a block diagram illustrating details of a fundamental wave current control unit according to the embodiment of the present invention.

FIG. 3 is a block diagram showing details of a harmonic current compensator in one embodiment of the present invention.

FIG. 4 is an explanatory diagram of an operation of a harmonic current compensator in one embodiment of the present invention.

FIG. 5 is a waveform chart for explaining an operation of the embodiment of the present invention in comparison with a conventional technique.

FIG. 6 is a block diagram showing details of a harmonic current compensator in another embodiment of the present invention.

FIG. 7 is a block diagram showing a harmonic current compensator in yet another embodiment of the present invention.

FIG. 8 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 9 is a flowchart showing the operation of still another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 2 AC reactor (ACL) 3 PWM converter main circuit 4 Smoothing capacitor 5 Load 6 DC voltage detector 7 DC voltage controller 8 AC voltage detector 9 Power supply voltage phase calculator 10 Current detector (CT) 11 Basic wave Current control unit 12 UVW / dq conversion processing unit 13 Non-interference current control processing unit 14 dq / UVW conversion processing unit 15 Harmonic current compensation unit 16 Harmonic reference phase calculation processing unit 17 Each order harmonic current calculation processing unit 18 Each order Harmonic compensation voltage calculation processing section 19 PWM signal generation section 20 3-phase / 2-phase converter 27 Harmonic compensation order setting device

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Fujii 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd. Industrial Equipment Division (56) References JP-A-1-298959 (JP, A) JP-A-8-80052 (JP, A) JP-A-6-276746 (JP, A) JP-A-7-123726 (JP, A) JP-A-8-23679 (JP, A) (58) Fields investigated Int.Cl. ⁷ , DB name) H02M 7/155 H02M 7/219

Claims (3)

(57) [Claims] In the pulse width modulation converter apparatus having an AC reactor between the 1. A 3-phase AC power supply and a pulse width modulation converter main circuit, and the voltage phase detection value of the 3-phase AC power source, the pulse width modulation converter main a voltage detection value of the direct current side of the circuit, based on the current detection value of the AC reactor, and the fundamental wave current control means the current flowing in the AC reactor to output the converter voltage command of the fundamental wave so that the sinusoidal Detecting a harmonic current component of a current flowing through the AC reactor based on a voltage phase detection value of the three-phase AC power supply and a current detection value of the AC reactor, and performing converter compensation so as to suppress the harmonic current component. And a harmonic current compensating means for outputting a voltage command, wherein the harmonic current compensating means reduces a voltage drop in the AC reactor.
A pulse width modulation converter device comprising: means for calculating a lower component, wherein the pulse width modulation converter main circuit is controlled by an output obtained by adding the converter voltage command of the fundamental wave and the converter compensation voltage command. 2. The pulse width modulation converter device according to claim 1, wherein the harmonic current compensating means calculates a fixed coordinate axis component from a harmonic reference phase of each order and a detected value of a current flowing through the AC reactor. Means for calculating a harmonic current component of each order of the AC reactor current via a dq converter for converting the component into a rotational coordinate axis component, and means for calculating a harmonic voltage component corresponding to the harmonic current component of each order And a means for outputting a compensation voltage command for the pulse width modulation converter via a proportional-integral compensator or an integral compensator based on the operation result of the harmonic voltage component. 3. A according to claim 1 or claim 2
In the pulse width modulation converter device, in the harmonic current compensation means, the order of the harmonic current components to be compensated, selected by manual operation can be set
That means the pulse width modulation converter device, wherein a is provided.